What do you mean by "when adding a Date column"? Do you mean to perform CRUD operations on the grid like adding, updating, deleting? In this case you should enable Updating feature as well. Please give me more details around your issue cause I'm not sure I understood it properly.

I was able to reproduce your issue and logged an internal bug in our system, so that our developers could take a look at it and suggest a fix. I've also opened a private case for you where this issue is attached. The case is with number: CAS-186324-K3Y8W5 and the bug is with id: 241035.

After further investigation of this matter, it seems that from v17.1 the igDataSource doesn't accept Microsoft date formatting (/Date(1234656000000)/). So if the provided data source contains this kind of data you should change it to ISO UTC format, for example: "2009-02-15T00:00:00Z". Here is an article related to this for your reference: https://www.igniteui.com/help/migrating-enableutcdates-option-in-17-1If you have any questions, please let me know.

From 17.1 when the date is serialized in the Microsoft format, the data source is not able to de-serialize it properly and keeps it as this string. This may give the impression that some operations work (like sorting) because the data source will execute them on the stored strings and under certain conditions the Microsoft-formatted date will have the same sorting result as the one from sorting the actual dates. Other features, like Filtering, try to execute date-specific expressions on these strings and fail.

As for the issue with the hidden column, this has been determined to be a bug and similarly to the previous one I logged it in our internal tracking system with ID: 241197.

Please note that you will be automatically notified in the case I created previously, once the issue is resolved.